Method and apparatus for treating felt



Nov. 30, 1943.

F. G. SOMMERVlLL-E METHOD AND PPARATUS FOR TREATING FELT Filed July 27, 1940 2 Sheets-Sheet l Nov. 30, 1943. F. G. soMMERvlLLE METHOD AND APPARATUSv 'FOR TREATING FELT Filecl July 27, 1940 Patented Nov. 3, i943 METHGD AND APPARATUS FR TRETING FELT Application July 27, 1940, Serial No. 347,942

8 Claims.

This invention relates to a method and apparatus for treating felted ,brous webs and finds particular usefulness in the manufacture of vibration damping and sound absorbing materials. The treated web will, of course, be useful for other purposes where the characteristics imparted to the web by my treatment may be found desirable.

Felt and felted products, with or without waterproong or binders, have been used as sound damping and sound absorbing agents in connection with vibratile metal sound producing and transmitting surfaces, such as le cabinets, office furniture, vehicular and automobile bodies, machinery pads, partition and wall constructions, and generally wherever a relatively cheap, easily applied material may advantageously be employed to reduce or inhibit the production or transmission of sound. FeltV as produced by the usual water laying methods has not been entirely saterty is undesirable in the formation of vibration and sound damping and absorbing materials intended to be conformed or applied to surfaces other than planar.

According to my invention, a felted product, suitable for use as a vibration and sound damping and absorbing material, is produced with a high degree of uniformity with respect to its flexing properties and in a much softer, less boardy" condition than is customarily available in unindented sheets.

An object of the invention is to provide a method whereby felt or felted sheets, before or after impregnation with waterproofing or binders; are subjected to a combination of .treatments comprising working the bers by a deformation of alternate areas transverse of the sheets andv v 8 and 9 and rthe channel A the drawingsUflhe bed i2 "arries bea-ring blocks;

Figure 2 is an end elevation of the apparatus partially in section taken on line A-A of Figure 1;

Figure 3 shows a detail sectional view of the surface of the corrugated roll takenon line C-C of Figure 4;

Figure 4 is a developed view of the corrugated surface shown in Figure 3; and

Figure 5 is an enlarged detail view of the roller pressure adjusting means.

To obtain the material to be used in my invention; I may produce a felted brous sheet which is preferably predominantly rag fiber,-on a paper machine, which felt when dried andfnished the usual Way is in the neighborhood of thick and of the order lof 11/8 pounds per square yard,

being somewhat less dense than rooing'felt. This sheet isrenderedwater resistant by the addition of asphalt or flux oil in such amountsfthat the voids of the sheet are not completely filled, as, for example, is commonly done in flooring felts. Alternatively, I may take any felted fibrous sheet which has been made in any suitable wayand subject it to the following process, which process constitutes my invention.

According to my invention, the felt, saturated or not, is subjected to a loosening treatment*` by means of corrugating rolls in conjunction 'with further loosening accompanied with a smoothing' of the sheet into alevel-surfacedmaterial by means of differentially driven rolls. 'v

A -suitable apparatus for performing these treatments is illustrated in the figures of the drawings in which FiguresI 1 and 2 show thegeneral form of the entire apparatus. The'jappaupright beams 4 any suitable means, suchasbythecrossbeams 2 .and'j I 3 shown on I4, i5, and "iS-"atene As1 e and corresiionding.- blocks on the other side rotatably supporting these between them."As .hereinpshowm these blocks each have a pair of uprights I8 and i9 (as illustrated with respect to block I4 in Figure 1) to which is xed a cross member 23, and the slide hich Il is shown in` suitable means for eral pairs-of calen-. dering rolls 3| and 32, v 3*Ifaiid 32","and- 3I'"-'jan'dl 32 therein andlmeans for, adjusting the pressure. exerted bythe rollsiupon the web'of feltl F passingl bearings and 2| have grooves 22 which are complementary to the upright pieces I8 and I9 for relative movement vertically with respect thereto. The uppermost slide `bearing 2| has a bearing plate 29 upon it against which a spring 26 is pressed by means of the plate 25. The pressure exerted by the spring upon the upper slide bearing 2| is adjusted by means of screw 24 which engages a screw thread in cross piece 23 and has a shoulder 21 which bears against the vertically movable plate 25. See the detail View in Figure 5 The spring bearing plate 29 is provided with a cylindrical projection 30 to maintain the spring in place. The projection 28 on plate 25 performs the corresponding function at the top portion of the spring.

Rolls 3| and 32 are supported by means of their trunnions 33 and 34 in their slide bearings 20 and 2| respectively for rotation therein, and

the trunnions carry gears and` 36 respectively at one end thereof. Rolls 3|', 32', 3|" and 32" are similarly arranged.- Between the pairs of blocks |4, |5 and l5, i6 respectively, are placed bearings 31 and 31' which carry shafts 39 and 33 and gears 38 and 38', said gears being of the same diameter and pitch as gears 3|, 3|', and 3 with which they mesh.

On the upper platform, bearing blocks 40 similar to blocks l|4 to I1 already described are provided with corrugating rolls 4| and 42, the trunnions of which each carry at one end thereof gears of identical pitch and diameter, 43 and 44. The bed at one end' has suitable supports for the core of a supply roll 45 and at the other end has supports 46 provided with I slot guides 41 therein for permitting the core v48 of the wind-up roll to be vertically displaced.

The lower corrugating roll 4| and the lower calendering roll 3| have their trunnions provided with sprockets by' means of which all the corrugating and calendering rolls are driven, power being taken oi the motor 54 from sprocket through chain 49. The trunnion 33 in block I6 has an additional sprocket 63 which drives chain 50 and roll 5| of the friction type, said roll 5| operating the wind-up roll through the agency of friction rolls 52 and 53 with which it engages.

The whole mechanism is driven by means of the motor 54 through the sprocket 55 and the interconnecting chains 49 and 5|l. Suitable idle rolls 56, 51, 58, 59 and 60 are positioned as shown to facilitate passage of the web F of felt successively through the series of paired rolls.

Figures 3 and 4 show detail views, the former in cross section and the latter in elevation, of one suitable form of corrugating roll. In the embodiment shown, projections 6| are generally pyramidal and are separated by depressions 62 so that the complementary projections of one roll will be -aligned with the depressions of the complementary roll, the distance between the outermost faces of theprojiections of one roll and the depth of the depressions in the complementary roll at the point of their nearest approach being such that the thickness of the felt is not greatly altered during the 'passage through such rolls.

In the operation of the machine, the felt web travels in the direction indicated by the arrows and is taken from the supply roll 45 over the idle rolls 56, 51 and 58 between the corrugating rolls4l and 42 where it is deformed by the projections of the rolls and is thereby worked, after which the web passes over idle roll 59 and then through the series of pairs of 'differentially driven rolls.' The differential effect is the result of the difference in sizeof gears 36 and 35 on rolls 3| and 32 (identical pairs of gears on the rolls 3|', 32', 3|", and 32" imparting differential speeds thereto) said gear 36 being smaller in diameter and having fewer gear teeth than said gear 35, with which it meshes, thereby causing roll 32 to have a higher surface speed than roll 3| and causing further Working 0f the fibers and leveling of the surfaces of the sheet passing between the rolls. The treatment in these calendering rolls may be facilitated by means of lubricating oil, such as kerosene, which is supplied by the wicks 64, 65, 66 dipping into the tanks 61, 68, 69 beneath the lower rolls 3|, 3|', and 3|. respectively. The lubricant may be app-lied to only one or two of the pairs of calendering rolls, but preferably it is applied to all pairs of differentially driven rolls. After passage through the differential calendering rolls, the web goes over idle roll and under friction rolls 52 and 53, back over rolls 53 and 52, and then on the wind-up roll on core 48. The application of the lubricant to the rolls prevents sticking and tearing of the felt and assists the dissipation of heat generated by the slip of the felt web lupon the faster moving rolls.

A similar lubricating arrangement may be applied to one of the corrugating rolls but this is not essential.

I have found that with a series of three pairs of differentially driven rolls, as illustrated, the difference between the surface speed of the rolls in each set may be from 10% to 15% -of the speed of the fastest roll of the pair, and yield a satisfactory commercial product. Tli manipulation of the sheet withthe corrugating and calendering rolls is preferably done after partial saturation of the sheet by the waterproofing ingredient, such as asphalt or flux oil, for the effect of such partial saturation is to bind the bers at their points of contact, to generally stiffen and strengthen the sheet. Furthermore, if the waterproofing ingredient is first put into the sheet, the softening effected by the corrugating and differential working treatment permanently characterizes the sheet after such treatment. If the sheet is treated with the corrugating and the differential working prior to saturation, or partial saturation, the softening eectis not as great and subsequent saturation or partial saturation llocks the fibers to a relatively stiffer structure. Where the sheet is to be used as a base or body for floor coverings or the like, a lesser degree of softening is generally satisfactory, but. as with vibration damping and sound absorbing felts, the preferred procedure is to effect a softening after the waterproflng agent has been incorporated into the we As illustratedby the drawings, the web F is first engaged by the corrugating rolls and then one surface of the web is engaged by the high speed rolls to effect the final working. Thus the web is subjected simultaneously at spaced points along its length to distinct types of mechanical working. The effect of the corrugating rolls which are complementary in surface configuration and have projections spaced at regular intervals and of any suitable shape, such as truncated pyramids or cones, is to deform the sheet by offsetting outwardly from one side of the sheet spaced areas corresponding to the projections on the corrugatlng rolls and oisettlng outwardly from the other side of the sheet other areas spaced between the rst mentioned areas and corresponding to the projections on the other rolls.. Such displacement results in loosening the fibers and, by increasingA the effective thickness yof the sheet, makes the subsequent treatment by differential rolls correspondingly more effective to thereby thoroughly soften the sheet. The differential rolls remove the indentations and projections in the sheet so that a sheet having substantially fiat faces results.

Other forms and arrangements of projections and depressions may be used on the corrugating rolls instead of those shown in the drawings. For example, pyramidal proJections having three or six or any other number of sides may be used and the depressions may have other shapes, and the projections may be arranged at the corners of triangles, -hexagons, and so forth, instead of at the corners of squares as shown.A Of course, the projections of one roll should, in this instance, be arranged to mesh properly with the projections of the other. Alternatively, one of the corrugating rolls may be replaced by a smooth-faced roll so that the working of the feltweb produces indentations on only one side of the web. Or this treatment may be followed by a second treatment between such a combination of smooth and corrugated rolls so arranged tnat the opposite side of the felt web is also worked by indentation.

While the drawings show the application of the corrugating rolls before treatment with the dii'- ferential calendering rolls, it is obvious that the cori'ugating treatment may be applied between any two pairs ofthe differential calendering rolls. Also, a greater or lesser number of pairs of differential rolls from that shown in the drawings may be applied, the larger the number of rolls. the more softening that will result. It is preferred to subject the sheet to the corrugating rolls first because this makes the operation of the differential rolls more effectice in producing a.' given degree of pliability and softness in the product. While the'drawings `also show that the faster rolls of the diiferential pairs are above the felt web, they may be underneath instead, or they may alternate from above to below the sheet. My combination of corrugating and differential working treatment results in opening of the sheet, and the formation of pores (as well as the further opening of the pores already present in an unsaturated sheet when such a sheet is .subjected to the treatment) so that the finished the effect may be attributed` mainly to loosening of the bers of the web by the combination or' treatments. I have also found that the flexibilizing effect is enhanced by increased pressure between the differential rolls, although high pressure alone does not give the desired effect, and

,- has the undesirable effect of permanently reducing the thickness of the sheet resulting in a more dense product with decreased vibration damping and sound absorbing properties. Ihe degree of pressure which 1 prefer maintained between the differential rolls is such that the felt is firmly pressed in the nip of the rolls but the thickness of the sheet is not permanently decreased more than in the neighborhood of 5% or 6% of its thickness before treatment. I believe that the softening effect of the differential rolls is due to a crowding of the felt by each of the higher speed rolls into a nip through which it can travel only at the speed of the complementary slower vspeed roll, resulting in an intense working of the felt to loosen the flbers thereof. I do not wish to be Vlimited to any particular theory of operation, for

whatever action takes places in my treatment, the result is a surprising increase in the flexibility and conformability of the product,l .together with a material increase in the vibration damping and sound-absorbing properties.- Tests hav'ealso indicated that the susceptibilityof the sheet' to'expand and contract upon absorption Y and release of moisture is materially reduced by treated material presents a surface requiring a minimum amount of adhesive to secure it to another' surface, possesses pores for the escape of solvents of such adhesive,if the adhesive be of the solvent type, and, although water-repellent, is nevertheless substantially.symmetrically flex--v ible and possessed of enhanced vibration and sessed of a highdegree of flexibility to conform` to angular and rounded surfaces. The flexibilthis treatment.v Reduction of this tendencyis desirable in surface coverings where dimensional changes will cause buckling.

The combination of the corrugatingrrolls with the dilferential calenderingrolls is a distinct improvement over the method described in the application of E. A. Worm, `J r., Serial No. 325,059, filed March 20,1940, .now Patent No. 2,229,401, only dierential calendering rolls are used, in that the material. produced by the new process is more flexible and porous than that'of the prior mentioned application, such increase in flexibility permitting the felt to conform more readily to the complex contours of automobile bodies and other pressed steel bodies, and the increase in porosity permitting a more rapid escape of the solvent present in the adhesiveused to adhere the belt to the metal body.

While I have illustrated and described the present preferred embodiment of my invention, it will be understood that it may be otherwise practiced and embedded within the scope of the following claims.

I claim: x

1. In an apparatus for treating a felt web, the combination of means comprising a pair of rotatable rolls having intermeshing projections thereon for deforming said web transverse to its plane at numerous small areas, rotatable bear- I ing means spaced from said deforming means 'pressing means tangentially of the web at the .thereon for deforming said web transverse to its plane at numerous small areas, rotatable bearing means spaced from said deforming means, a roller adjacent said bearing means, means for passing said web between the roller and bearing means, means for adjusting the space between the roller and bearing means, and-means for rotating the roller at a tangential speed greater .than the speed of the feb between the roller and bearing means to effect a pulling and stroking of the bers in the web to a condition wherein the two web faces lie substantially in-parallel flat planes.

3. In an apparatus for treating a felt web, the combination of a pai of corrugating rolls for deforming said web and forming projections and depressions in the two web faces, a pair ofv opposed pressure rolls for calendering said web, means for driving one roll of said pair of pressure rolls at a speed greater than that of the opposed roll to eect a pulling and stroking .of the fibers in the web, and means for conveying the web between the rolls of each pair.

4. In the method of -producing a vibrationdamping felt web having improved flexibility and pliability characteristics, the steps of deforming the web while in a substantially dry condition by offsetting alternate areas along lines transverse of the web to opposite sides thereof and differentially calendering at least one surface of the web with a force parallel to the plane of the web to effect a pulling and stroking of the fibers in the web and expanding of the web to a condition wherein the two faces lie substantially in parallel flat planes with no noticeable decrease in thickness of the deformed web.

5. In the method of producing a vibrationamping felt web having improved flexibility and pliability characteristics, the steps of deforming the web while in a substantially dry condition by offsetting alternate areas along lines transverse of the web to opposite sides thereof, and then differentially calendering at least one surface of the web at each of several spaced points therealong with a force parallel to the plane of said web to effect a pulling and stroking of the fibers in the web and an expanding of the web to a condition whereinl the two surfaces lie .substantially in parallel fiat planes with no noticeable decrease in thickness of the deformed web.

6. In the method of producing a vibrationdamping felt web having improved flexibility and pliability characteristics, the steps of deforming the web While in a substantially dry condition by offsetting alternate areas along lines transverse of the web to opposite sides thereof and then differentially calendering at least one surface of the web with a force parallel to the plane of said web to effect a pulling and stroking of the bers in the web' and an expanding of the web and then differentially calendering the opposite surface of the web with a force parallel to the plane of said web to effect further pulling and stroking of the bers in the web and an expanding of the web to a condition wherein the two surfaces lie substantially in parallel flat planes with no noticeable decrease in thickness of the deformed web.

7. In the method of producing a vibrationdamping felt web having improved flexibility and pliability characteristics, the steps of stretching the body of the web while in a substantially dry condition by displacing alternate areas thereof in the form of projections to opposite sides of the web whereby substantially no increase in average width or length of the sheet results and simultaneously differentially calendering and working the fibers in the web, at a point spaced from a point where the projection displacement is applied, by passing theweb between two pressure-applying surfaces which have different speeds tangential to the surface of the web and which exert a force parallel to the plane of the web, whereby such working of the fibers is accompanied by substantially no increase in the overall dimensions of the web.

8. In the method of producing a vibrationdamping, asphalt-impregnated felt web having improved flexibility and pliability characteristics, the steps of deforming the impregnated web while in a substantially dry condition by oisetting alternate areas along lines transverse of the web to opposite sides thereof and differentially calendering at least one surface of the web with a force parallel to the plane of the web to effect a pulling and stroking of the fibers in the web and expanding of the web to a condition wherein the two faces lie substantially in parallel at planes with no noticeable decrease in thickness of the deformed web.

FREDERICK G. SOMMERVUJF.

'CERTIFICATE CF CORRECTION. Patent No.' 2,555,1462. 'November 50, 19115.

FREDERICK C. somIERvIIIE.

It ,is hereby Certified that error appears in the prnte'd specification of the above numhered patent requiring correction as follows Page 5, first column, line )42, for '.'effectice" read -effective; and.- second Column, line 'ilrafter "Patent No. 2,229,1401'," insert --in which; line 6l, for belt read fehlt-r; page h, r11-st column,- IIne 13, for *feb* read --web; and that the said Letters Patent should. be read with this correction therein that the same may Confrmto the record of the case in the Patent Office.

signed and sealed this 25th day or January, A. n. 191m.

Henry Van Arsdale, (Seal) I Acting Commissioner of Patents. 

